Expression of PD-L1 Identifies a Subgroup of More Aggressive Non-Small Cell Carcinomas of the Lung

OBJECTIVES: In light of various trials showing impressive response rates when treating non-small cell lung cancer (NSCLC) patients with anti PD-1/PD-L1 antibodies, the currently equivocal role of PD-L1 expression in NSCLC is in need of further clarification. METHODS: We therefore analyzed the expression of PD-L1 on 293 well-documented NSCLC cases and correlated the results with clinical, histopathological and immunohistochemical characteristics. RESULTS: The expression of PD-L1 on NSCLC was a poor prognostic factor for patients with nodal-negative adenocarcinoma (ACA) and, independent of other covariates, in tumors with increased CD8+ tumor-infiltrating lymphocytes (TILs). Expression of PD-L1 was more commonly seen in ACA and in male patients with a past and current smoking history. Finally, PD-L1+ TILs were more often found in squamous and large cell carcinomas. CONCLUSIONS: Should the expression of PD-L1 be on the verge of becoming an additional biomarker for routine diagnostics in NSCLC, our findings will provide important further insight and could contribute towards more effectively stratifying patients. These results may single out certain patient groups with a potential for increased benefit from anti PD-1/PD-L1 treatment strategies and should be considered in future trials.